One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when it's a good idea to plant angel's trumpets by looking at the USDA zone info for Walla Walla.

Planting Calendar for Angel's Trumpets

Frost tolerance for angel's trumpets:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since angel's trumpets are barely cold tolerant you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant angel's trumpets in Walla Walla is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant angel's trumpets and expect a good harvest is probably August. You probably don't want to wait any later than that or else your angel's trumpets may not have a chance to grow to maturity. If you are starting your angel's trumpets indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Walla Walla. You can expect an average low temperature of 0°F in the coldest months of winter.

It's important to remember that USDA zone info for Walla Walla is just an average and the actual date of last frost is different every year. Since half of the time in Walla Walla there is a last frost after April 15 be ready to cover your angel's trumpets in the event of a late frost.

USDA Zone Info for Walla Walla

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Walla Walla

You may be interested in your other planting guides for Walla Walla.